import numpy as np
arr1 = np.array([1,2,3])
print('一维数组arr1:\n',arr1)
arr2= np.array((4.5,5.6,6.8),dtype='int32')
print('一维数组arr2:\n',arr2)
arr3 = np.array([[1,2,3],[4,5,6]], dtype='float32')
print('2*3的二维数组arr3:\n',arr3)

